[freetype2] master 9c51e21e5: [cff, truetype] Improve prefix and suffix removal.

[Werner Lemberg]

branch: master
commit 9c51e21e53e5a97e287b450b1784c3a0979603f0
Author: Alexei Podtelezhnikov <apodtele@gmail.com>
Commit: Alexei Podtelezhnikov <apodtele@gmail.com>

    [cff, truetype] Improve prefix and suffix removal.
    
    * src/cff/cffobjs.c (remove_style): Rewrite using pointers.
    (remove_subset_prefix): Unwrap loop and use `memmove`.
    * src/truetype/ttobjs.c (tt_skip_pdffont_random_tag): Unwrap loop
    and avoid `strlen`.
---
 src/cff/cffobjs.c     | 79 ++++++++++++++++-----------------------------------
 src/truetype/ttobjs.c | 24 +++++++++-------
 2 files changed, 37 insertions(+), 66 deletions(-)

diff --git a/src/cff/cffobjs.c b/src/cff/cffobjs.c
index 6d08620c4..4b710745f 100644
--- a/src/cff/cffobjs.c
+++ b/src/cff/cffobjs.c
@@ -421,32 +421,23 @@
   static void
   remove_subset_prefix( FT_String*  name )
   {
-    FT_Int32  idx             = 0;
-    FT_Int32  length          = (FT_Int32)ft_strlen( name ) + 1;
-    FT_Bool   continue_search = 1;
+    FT_UInt32  i = 0, idx = 0;
 
 
-    while ( continue_search )
+    /* six ASCII uppercase letters followed by a plus sign */
+    while ( 'A' <= name[i] && name[i++] <= 'Z' &&
+            'A' <= name[i] && name[i++] <= 'Z' &&
+            'A' <= name[i] && name[i++] <= 'Z' &&
+            'A' <= name[i] && name[i++] <= 'Z' &&
+            'A' <= name[i] && name[i++] <= 'Z' &&
+            'A' <= name[i] && name[i++] <= 'Z' &&
+                              name[i++] == '+' )
     {
-      if ( length >= 7 && name[6] == '+' )
-      {
-        for ( idx = 0; idx < 6; idx++ )
-        {
-          /* ASCII uppercase letters */
-          if ( !( 'A' <= name[idx] && name[idx] <= 'Z' ) )
-            continue_search = 0;
-        }
-
-        if ( continue_search )
-        {
-          for ( idx = 7; idx < length; idx++ )
-            name[idx - 7] = name[idx];
-          length -= 7;
-        }
-      }
-      else
-        continue_search = 0;
+      idx = i;
     }
+
+    if ( idx )
+      FT_MEM_MOVE( name, name + idx, ft_strlen( name + idx ) + 1 );
   }
 
 
@@ -456,42 +447,20 @@
   remove_style( FT_String*        family_name,
                 const FT_String*  style_name )
   {
-    FT_Int32  family_name_length, style_name_length;
+    FT_String*        f = family_name + ft_strlen( family_name );
+    const FT_String*  s =  style_name + ft_strlen(  style_name );
 
 
-    family_name_length = (FT_Int32)ft_strlen( family_name );
-    style_name_length  = (FT_Int32)ft_strlen( style_name );
+    /* compare strings moving backwards */
+    while ( s > style_name )
+      if ( f == family_name || *--s != *--f )
+        return;
 
-    if ( family_name_length > style_name_length )
-    {
-      FT_Int  idx;
-
-
-      for ( idx = 1; idx <= style_name_length; idx++ )
-      {
-        if ( family_name[family_name_length - idx] !=
-             style_name[style_name_length - idx] )
-          break;
-      }
-
-      if ( idx > style_name_length )
-      {
-        /* family_name ends with style_name; remove it */
-        idx = family_name_length - style_name_length - 1;
-
-        /* also remove special characters     */
-        /* between real family name and style */
-        while ( idx > 0                     &&
-                ( family_name[idx] == '-' ||
-                  family_name[idx] == ' ' ||
-                  family_name[idx] == '_' ||
-                  family_name[idx] == '+' ) )
-          idx--;
-
-        if ( idx > 0 )
-          family_name[idx + 1] = '\0';
-      }
-    }
+    /* terminate and remove special characters */
+    do
+      *f = '\0';
+    while ( f-- > family_name                                    &&
+            ( *f == '-' || *f == ' ' || *f == '_' || *f == '+' ) );
   }
 
 
diff --git a/src/truetype/ttobjs.c b/src/truetype/ttobjs.c
index 5b56af711..9126f9eab 100644
--- a/src/truetype/ttobjs.c
+++ b/src/truetype/ttobjs.c
@@ -152,18 +152,20 @@
   static const FT_String*
   tt_skip_pdffont_random_tag( const FT_String*  name )
   {
-    unsigned int  i;
-
-
-    if ( ft_strlen( name ) < 8 || name[6] != '+' )
-      return name;
-
-    for ( i = 0; i < 6; i++ )
-      if ( !ft_isupper( name[i] ) )
-        return name;
+    if ( ft_isupper( name[0] ) &&
+         ft_isupper( name[1] ) &&
+         ft_isupper( name[2] ) &&
+         ft_isupper( name[3] ) &&
+         ft_isupper( name[4] ) &&
+         ft_isupper( name[5] ) &&
+              '+' == name[6]   &&
+                     name[7]   )
+    {
+      FT_TRACE7(( "name without randomization tag: %s\n", name + 7 ));
+      return name + 7;
+    }
 
-    FT_TRACE7(( "name without randomization tag: %s\n", name + 7 ));
-    return name + 7;
+    return name;
   }